Research On Variable-Temperature Drying Craft Of Germinated Brown Rice

Germinated brown rice is product that brown rice was germinated under a certain temperature and humidity of environment, and then was dryed while germinating enough. In germinating, because self-contained enzymes was activated and released, brown rice contained rich Active Substance like GABA and ip-6, at the same time and retain abundant nutrients nutritive material such as vitamins(B1, B2, B6, C, E), minerals(magnesium, potassium, zinc, iron) dietary fiber etc. Consequently, germinated brown rice has more abundant nutritive value compared with brown rice and polished rice. The germinated brown rice enriches variety of rice and increase the auditory value of rice, so has an expansively developing prospect.Germinated brown rice relatively high the moisture content, for the traditional method of invariable temperature drying, it would be take longer time if we adopt a lower temperature, so the drying is time-cost and high energy consumption. For the high temperature method, it has an adverse effect on drying qualities of germinated brown rice. Because of the high temperature of material, we have to design suitable material, to solve the problem of drying germinated brown rice. So the method should be designed, which is adaptable for the material characteristics. Variable-temperature drying helps to smooth away both problems. When higher moisture content, will use the high temperature drying. When lower moisture content, will use the low temperature drying, and ensure that the temperature of germinated brown rice will be less than60℃, in order to ensure the drying qualities.In this paper we discuss two-side problems. First, the system of experimental platform is built and the design of control system is finished. Second, how to dry the germinated brown rice; how to produce as much as possible without damaging germination nutrients and optimize the parameters in the drying process; etc.(1) Structures of the experiment system and the design of control systems. This subject adopts hot air drying equipment, which is consisted of the electric, drying chamber, the main circulating fan, the corresponding sensors, data acquisition system. Through self-designed data acquisition devices capture the drying process and drying of materials media, real-time information. The input of the system is the temperature and humidity of the dry cabinet while the controlling objects are the switch of electric heater in dry cabinet. PID method is used to adjust the temperature of the system in the controlling system, which could get the requirement of drying process in different drying phase and advance the drying quality and save resource. The system consists of LTM-8663Dual-CPU-based Strong long-range control model, LTM-8520RS232/485Isolated Converter, JSA12M Analog control electric actuator, exhaust fan, IPC, etc. The host computer controlling in different phase is based on the software which developed by C++. The function of the system contains, collecting information, data display, regulating temperature controlling, automation or manual controlling, etc. After all, it is energy saving and environmental protection, drying capacity, computer-controlled high-performance drying system.(2) Single-factor test to explore the various factors on the drying rate and energy consumption effects. The results showed that temperature, wind speed increased, drying rate increased accordingly. When the temperature is above95℃, wind speed at3.6m/s and above, the drying rate did not change significantly. Unit energy consumption decreases with increasing temperature and increases with increasing wind speed. According to the experimental data, we boost the material of the drying curve and drying rate curves, in order to determine the germinated brown rice drying technology provides a technological means and data for reference.(3) A drying experiment with temperature variable is carried out on the model laboratory-scale drying equipment. Taking the heated air temperatures in the first and the last stages, the moisture content at which the air temperature changes and the wind speed as4factors, and with the drying rate and specific energy consumption as2optimization targets, the drying process of Germinated Brown Rice were simulated with various temperature. Through single factor and multivariate analysis on all experimental indexes, the law that various factors influence property index. By multiple linear regressions we obtain the performance index of multiple single-objective regression equation, the establishment of germinated brown rice drying performance of Regression model.(4) Optimized parameters were obtained by simulation and optimization of the drying process. The optimization of multiple objectives was converted into that of single objective by weighting method. We obtain the most promising optimal solution by calling the functions in MATLAB toolbox. Optimization results are air temperature in advance is103.9℃, the last air temperature is55.7℃, moisture content is34.9%and wind speed is 3.57m/s. At this point drying rate is4.034%-h-1, unit energy consumption is12.816*103·KJ·(kgH2O)-1.